Compressor blade with nozzle

ABSTRACT

A compressor blade having at least one nozzle for ejecting fluid, in particular for ejecting water, is provided. The at least one nozzle is produced as a laminar structure in which, in particular, individual layers such as metal sheets are laid on top of each other, and has differently orientated channel sections of a channel between an inlet and an outlet, wherein the metal sheets have cutouts corresponding to the channel sections. The nozzle geometry makes it possible to prevent the formation of droplets as water exits a compressor blade.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International Application No. PCT/EP2012/063816 filed Jul. 13, 2012, and claims the benefit thereof. The International Application claims the benefit of German Application No. DE 102011079195.7 filed Jul. 14, 2011. All of the applications are incorporated by reference herein in their entirety.

FIELD OF INVENTION

The invention relates to a compressor blade having nozzles for injecting a fluid into the compressor.

BACKGROUND OF INVENTION

Gas turbines can be operated with what is termed wet compression, in which a fluid is injected, inside the compressor of the gas turbine, into the air flowing through the compressor and which is to be compressed therein.

However, this gives rise to the danger of drop formation, which can in turn lead to drop impingement erosion and thus to damage to downstream blades.

SUMMARY OF INVENTION

It is an object of the invention therefore to solve the abovementioned problem.

The object is achieved by means of a compressor blade as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-12 show exemplary embodiments of the invention,

FIG. 13 shows a gas turbine.

DETAILED DESCRIPTION OF INVENTION

The description and the figures show only exemplary embodiments of the invention.

FIG. 1 shows a cross section of a blade airfoil, in particular of a compressor blade 4, which, in particular at its leading edge or incident flow region 5 and downstream therefrom on the suction face and/or pressure face, has a plurality of nozzles 6, 6 ^(I), 6 ^(II), . . . , out of which a fluid 7, in particular water, exits.

This is used for wet compression when operating a gas turbine 100 (FIG. 13).

The suction and pressure faces can feature the same number or different numbers of nozzles 6, 6 ^(I), 6 ^(ii). . .

In particular, a nozzle 6, 6 ^(I), . . . is present in the leading edge 5.

Perpendicular to the plane of the drawing, more nozzles 6, 6 ^(I), . . . can be present at the leading edge 5 and/or on the suction face or pressure face.

The compressor blade 4 usually has, inside it, a hollow space 3 which is surrounded by walls 2 and by means of which the fluid can be fed to the nozzle 6 ^(I).

FIG. 2 shows a section through such a nozzle 6 ^(I), which may be arranged in the suction face wall 2 or the pressure face wall 2 of the compressor blade 4.

In the wall 2 of a hollow compressor blade 4 there is a channel 40 consisting of a plurality of channel sections 25 ^(I), 28 ^(I), 29 ^(I), 31 ^(I), 32 ^(I) which form the nozzle 6 ^(I).

Each channel section 25 ^(I), 28 ^(I), 29 ^(I), 31 ^(I), 32 ^(I), . . . is preferably generally straight or preferably features a deviation of <8°.

The channel sections 25 ^(I), 28 ^(I), 29 ^(I), 31 ^(I), 32 ^(I), . . . are as close as possible to an outer surface 26 of the compressor blade 4 (generally only as an example of a blade).

The water (only as an exemplary fluid) flows through an inlet 19 ^(I) into a first channel section 25 ¹ which preferably extends more or less parallel to the outer surface 26 as far as the section 28 ^(I), when the channel 40 effects a 90° diversion to run perpendicular to the surface 26, only to effect another 90° diversion, into channel section 29 ^(I), so as to run in the same direction as channel section 25 ^(I). Channel section 31 ^(I) effects a 180° diversion into channel section 32 ^(I), which runs parallel to the surface 26 and thus in the opposite direction to the flow in the first channel section 25 ^(I), finally opening into an outlet opening 16 ^(I); thus overall 90°/180° or 180°/90° as in FIG. 8.

This pattern for the channel sections 25 ^(I), 28 ^(I), 29 ^(I), 31 ^(I), 32 ^(I) is only exemplary.

FIG. 3 shows a further modification to the exemplary embodiment of FIG. 2.

The difference lies in the fact that the inlet 19 ^(II)is downstream of the outlet 16 ^(II), as seen in a longitudinal direction, for example the direction of flow 43 over or around the compressor blade 4, whereas in FIG. 2 the inlet 19 ^(I) is upstream of the outlet 16 ^(I).

In FIGS. 2 and 3, a 90° bend is followed by a 180° bend.

It is also possible for a 180° bend to be followed by a 90° bend (FIG. 8).

Another exemplary embodiment is shown in FIG. 4, in which only one channel section 32 ^(III) is present, such that the fluid, proceeding from the inlet 19 ^(III), is redirected only once through 90°.

The inlet 19 ^(III) may also lie upstream of the outlet 16 ^(III), as seen in the direction 43.

FIG. 5 shows a further exemplary channel 40.

The channel 40 has three sections 25 ^(IV), 31 ^(IV), 32 ^(IV), i.e. it features one 180° bend.

The inlet 19 ^(IV) can in this case lie upstream (FIG. 5) or downstream of the outlet 16 ^(IV), as seen in the direction of flow 43.

A nozzle of this type 6, 6 ^(I), 6 ^(II), . . . can also be produced separately and is then inserted as a module 22 into a recess 23 in the compressor blade 4 (FIG. 7).

The nozzle 6 ^(I), 6 ^(II), . . . can be a single opening 16 ^(I), . . . or can also be an annular arrangement of individual openings 7 ^(I), 7 ^(II), . . . , as shown in FIG. 6.

The nozzle 6 ^(I), 6 ^(II), 22 is preferably produced as a laminar structure in which, in particular, individual layers such as metal sheets, having cutouts corresponding to the channel sections 25, 28, 29, 31, 32, are laid on top of each other. This is shown in exemplary fashion in FIG. 4. It is also possible for the nozzle 6 ^(I) or the module 22 to be produced using a rapid prototyping process, or the entire compressor blade 4 is produced in this manner.

The nozzle 6 ^(I), 6 ^(II), . . . , 22 is preferably cast-in, i.e. it is prefabricated and inserted into the casting mold and material is then cast around it.

FIG. 9 shows a further exemplary embodiment of the invention (6 ^(VIII)).

Here, too, there is a channel section 32 ^(VIII) featuring a deviation which, in contrast to FIG. 4, is not 90° but is at an angle >10° and <80°, in this case preferably 45°, to the surface 26.

FIG. 10 (6 ^(V)) shows a further slight modification to FIG. 9, in which another channel section 25 ^(V), which runs approximately parallel to the direction 43 of the flow over the blade or parallel to the surface 26, is present.

FIGS. 11 and 12 show modifications to the exemplary embodiment of FIG. 5 (or combination with the figures/exemplary embodiments in which a 180° bend occurs).

FIGS. 5 and 12 both feature a 180° diversion, although in the latter case this is achieved by means of a curved channel section 31 ^(X).

Equally preferably, the channel section 31VII can be given by a plurality of channel sections wherein, by corresponding deflection, an overall diversion of 180° is achieved (FIG. 11). In this case, for example, a 45° diversion is followed by a 90° diversion and then by another 45° diversion.

In particular, the channel sections 25 ^(I)-32 ^(I), . . . are in a flat arrangement.

The channel 40 always features at least one deviation, i.e. a diversion of between 10° and 180°, 90° or 180°.

The cross section of the channel 40 or, respectively, of the channel sections 25 ^(I), 28, . . . is preferably rectangular.

The channel 40 is supplied through the blade root and/or in the case of guide vanes through the upper vane platform.

For the purposes of the invention, the outlet 16 ^(I), . . . and/or the inlet 19 ^(I), . . . are not considered to be a channel section featuring a diversion. These nozzles 6, 6 ^(I), . . . have the general advantage that no droplets form, this being achieved, according to the invention, by means of the bends inside the channel 40.

FIG. 13 shows, by way of example, a partial longitudinal section through a gas turbine 100.

In the interior, the gas turbine 100 has a rotor 103 with a shaft 101 which is mounted such that it can rotate about an axis of rotation 102 and is also referred to as the turbine rotor.

An intake housing 104, a compressor 105, a, for example, toroidal combustor 110, in particular an annular combustor, with a plurality of coaxially arranged burners 107, a turbine 108 and the exhaust-gas housing 109 follow one another along the rotor 103.

The annular combustor 110 is in communication with a, for example, annular hot-gas passage 111, where, by way of example, four successive turbine stages 112 form the turbine 108.

Each turbine stage 112 is formed, for example, from two blade or vane rings. As seen in the direction of flow of a working medium 113, in the hot-gas passage 111 a row of guide vanes 115 is followed by a row 125 formed from rotor blades 120.

The guide vanes 130 are secured to an inner housing 138 of a stator 143, whereas the rotor blades 120 of a row 125 are fitted to the rotor 103 for example by means of a turbine disk 133.

A generator (not shown) is coupled to the rotor 103.

While the gas turbine 100 is operating, the compressor 105 sucks in air 135 through the intake housing 104 and compresses it. The compressed air provided at the turbine-side end of the compressor 105 is passed to the burners 107, where it is mixed with a fuel. The mix is then burnt in the combustor 110, forming the working medium 113. From there, the working medium 113 flows along the hot-gas passage 111 past the guide vanes 130 and the rotor blades 120. The working medium 113 is expanded at the rotor blades 120, transferring its momentum, so that the rotor blades 120 drive the rotor 103 which in turn drives the generator coupled to it.

While the gas turbine 100 is operating, the components which are exposed to the hot working medium 113 are subject to thermal stresses. The guide vanes 130 and rotor blades 120 of the first turbine stage 112, as seen in the direction of flow of the working medium 113, together with the heat shield elements which line the annular combustor 110, are subject to the highest thermal stresses.

To be able to withstand the temperatures which prevail there, they may be cooled by means of a coolant.

Substrates of the components may likewise have a directional structure, i.e. they are in single-crystal form (SX structure) or have only longitudinally oriented grains (DS structure).

By way of example, iron-based, nickel-based or cobalt-based superalloys are used as material for the components, in particular for the turbine blade or vane 120, 130 and components of the combustor 110.

Superalloys of this type are known, for example, from EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949.

The blades or vanes 120, 130 may likewise have coatings protecting against corrosion (MCrAlX; M is at least one element selected from the group consisting of iron (Fe), cobalt (Co), nickel (Ni), X is an active element and stands for yttrium (Y) and/or silicon, scandium (Sc) and/or at least one rare earth element, or hafnium). Alloys of this type are known from EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 1 306 454 A1.

It is also possible for a thermal barrier coating to be present on the MCrAlX, consisting for example of ZrO₂, Y₂O₃-ZrO₂, i.e. it is unstabilized, partially stabilized or fully stabilized by yttrium oxide and/or calcium oxide and/or magnesium oxide.

Columnar grains are produced in the thermal barrier coating by suitable coating processes, such as for example electron beam physical vapor deposition (EB-PVD).

The guide vane 130 has a guide vane root (not shown here), which faces the inner housing 138 of the turbine 108, and a guide vane head which is at the opposite end from the guide vane root. The guide vane head faces the rotor 103 and is fixed to a securing ring 140 of the stator 143. 

1-14. (canceled)
 15. A compressor blade comprising: at least one nozzle for ejecting fluid, wherein the at least one nozzle is produced as a laminar structure wherein individual layers are laid on top of each other, and wherein the at least one nozzle has differently orientated channel sections of a channel between an inlet and an outlet, wherein the individual layers have cutouts corresponding to the channel sections.
 16. The compressor blade as claimed in claim 15, wherein the channel between the inlet and the outlet is diverted at least once.
 17. The compressor blade as claimed in claim 15, wherein the channel between the inlet and the outlet is diverted at least twice.
 18. The compressor blade as claimed in claim 15, wherein the channel between the inlet and the outlet is diverted only twice.
 19. The compressor blade as claimed in claim 15, wherein the channel between the inlet and the outlet is diverted only once.
 20. The compressor blade as claimed in claim 15, wherein the channel is diverted by between 10° and 180°.
 21. The compressor blade as claimed in claim 15, wherein the channel is diverted by between 30° and 180°.
 22. The compressor blade as claimed in claim 15, wherein the channel is diverted by between 40° and 180°.
 23. The compressor blade as claimed in claim 15, wherein the channel is diverted by 90°.
 24. The compressor blade as claimed in claim 15, wherein the channel is diverted by between 30° and 70°.
 25. The compressor blade as claimed in claim 15, wherein the channel is diverted by 180°.
 26. The compressor blade as claimed in claim 15, wherein the channel sections are straight.
 27. The compressor blade as claimed in claim 15, wherein the at least one nozzle is provided as a module and is adapted to be inserted into a recess in the compressor blade.
 28. The compressor blade as claimed in claim 15, wherein the at least one nozzle comprises an annular or oval arrangement of individual holes.
 29. The compressor blade as claimed in claim 15, wherein the at least one nozzle is located within a wall of the compressor blade.
 30. The compressor blade as claimed in claim 15, wherein the at least one nozzle is located at the leading edge.
 31. The compressor blade as claimed in claim 15, wherein the at least one nozzle is located on the suction face and/or on the pressure face, and is adapted so that the fluid can be fed through the inside of the compressor blade.
 32. The compressor blade as claimed in claim 15, wherein the at least one nozzle is located at the leading edge and has a laminar construction, and wherein the material surrounding the at least one nozzle serves as a protective layer against drop impingement erosion.
 33. The compressor blade as claimed in claim 15, wherein the individual layers comprise metal sheets.
 34. The compressor blade as claimed in claim 15, wherein the at least one nozzle is adapted for ejecting water. 